Надо что бы вместе с кругами рандомно появлялись еще и квадраты отталкиваясь от стенок.

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls;
 
type
  TForm1 = class(TForm)
 
    Image1: TImage;
    Timer1: TTimer;
    procedure FormActivate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
type mySharik = record
  x,y,r:integer;
  dx, dy: integer;
  Color:TColor;
end;
 
var
  Form1: TForm1;
  a: array of mySharik;
 
implementation
 
{$R *.dfm}
 
procedure InitShariki;
var
 i, r: integer;
begin
  SetLength(a, 100);
  Randomize;
  for i:= 0 to High(a) do
   begin
     r:= random(100) + 5;
     a[i].x:= random(Form1.Image1.Width-r);
     a[i].y:= random(Form1.Image1.Height-r);
     a[i].r:= r;
     a[i].dx:= random(20) - random(20);
     a[i].dy:= random(20) - random(20);
     a[i].Color:=RGB(random(255), random(255), random(255));
   end;
end;
 
procedure PrintShariki;
var
 i:integer;
begin
  Form1.Image1.Canvas.Brush.Color:= clWhite;
  Form1.Image1.Canvas.Rectangle(0,0,Form1.Image1.Width,Form1.Image1.Height);
 
  for i:=0 to High(a) do begin
    Form1.Image1.Canvas.Ellipse(a[i].x,a[i].y,a[i].x+a[i].r,a[i].y+a[i].r);
    Form1.Image1.Canvas.Rectangle(a[i].x,a[i].y,a[i].x-a[i].r,a[i].y-a[i].r);
    Form1.Image1.Canvas.Brush.Color:= a[i].Color;
  end;
end;
 
Procedure MoveShariki;
var
  i: integer;
begin
  for i:= 0 to High(a) do begin
    a[i].x:= a[i].x + a[i].dx;
    a[i].y:= a[i].y + a[i].dy;
    if a[i].x < 0 then a[i].dx:= -a[i].dx;
    if a[i].x > Form1.Image1.Width -a[i].r then a[i].dx:= -a[i].dx;
    if a[i].y < 0 then a[i].dy:= -a[i].dy;
    if a[i].y > Form1.Image1.Height -a[i].r then a[i].dy:= -a[i].dy;
  end;
end;
 
procedure TForm1.FormActivate(Sender: TObject);
begin
  InitShariki;
  PrintShariki;
end;
 
procedure TForm1.Timer1Timer(Sender: TObject);
begin
  MoveShariki;
  PrintShariki;
end;
 
end.